Thread Machining; Thread Cutting G33/G34/G35/G37 - Siemens SINUMERIK 880 Programming Manual

4 Programming of Motion Blocks

4.3 Thread machining

4.3 Thread machining
4.3.1

Thread cutting G33/G34/G35/G37

It is an integral part of the E40-E45 spindle package
There are various types of thread which can be cut as follows:
• Threads with constant lead
• Threads with variable lead
• Threads on cylindrical or tapered elements
• External or internal threads
• Transversal threads
The following preparatory functions are available for machining threads:
• G33 Thread cutting with constant lead
• G34 Thread cutting with linear lead increase
• G35 Thread cutting with linear lead decrease
• G37 Thread cutting at various speeds
A maximum of 2 axes can be programmed with commands G33/G34/G35.
The thread length is entered under the corresponding path address; starting, stopping and
overrun sections at which the feedrate is increased or reduced must be taken into
consideration. The values can be entered using absolute or incremental position data.
The thread lead is entered under addresses I, J, K.
The lead is entered under K for longitudinal threads, under I for transversal threads and under I
and K for tapered threads. I, J and K must always be entered using incremental position data
and without sign. The standard input resolution of the thread lead is 0.001 mm/revolution.
The thread lead can be programmed between 0.001 mm and 400.000 or 2000.000 mm.
Right and left-hand threads are programmed by specifying the spindle direction of rotation
functions M03 and M04.
The spindle direction of rotation and the speed must be programmed in the block prior to the
actual thread cutting operation to permit the spindle to run up to its nominal speed.
The programming of "Fine exact stop" (G09) is not allowed in thread cutting blocks. If
nonetheless G09 is programmed or G60 is active, these are ignored.
Example:
L F
N10 S500 M03
L F
N15 G33 Z . . . K . . .
The feed start does not begin until the zero mark on the pulse encoder has been reached in
order to permit threads to be cut in several steps. This ensures that the tool always enters the
workpiece at the same point on the circumference of the workpiece. The cuts should be
performed at the same spindle speed to avoid different following errors.
4–54
The "Thread cutting G33/G34/G35/37"
function is an Option.
© Siemens AG 1991 All Rights Reserved
01.93
6ZB5 410-0HD02
SINUMERIK 880, (PG)